Shuttle system for internal pipe coating



' Jan. 21, 1964 D. K. MGLEAN SHUTTLE SYSTEM FOR INTERNAL PIPE coATING Filed Dec. 5. 1960 United States Patent O 3,118,791 SHUTTLE SYSTEM FUR INTERNAL PEPE CGATING Douglas K. McLean, Daiias, Tex., assigner to Harvest Queen Midi di Elevator Qompany, Dallas, Tex., a corporation of Texas Filed Dec. 5, 1960, Ser. No. 73,620 2 Claims. (Cl. 11S- 408) This invention relates to internal coating of sections of pipe and more particularly to a system of applicators which are adapted to be propelled in different directions through successive joints of pipe positioned in a treating Zone.

lt is well-known to utilize internal coatings on pipes as well as external coatings in order to prevent corrosion. internal coatings may also serve to increase the effective capacity of the pipe to conduct fluids therethrough. It is desirable to provide an internal pipe coating which may be readily applied which has the uniform characteristic throughout the entire length of a given section of pipe and which is relatively inexpensive in its initial application. The present invention is provided to permit coating of pipe sections or joints successively as they are moved through a treating zone wherein all pipe handling operations rnay be automatic and the coating thereof may be readily accomplished.

An object of this invention is to provide a more rapid means of applying a coating to the inside surface of pipe or tubular goods by providing for coating one section of pipe on a single stroke of the coating plugs, not requiring the return of those coating plugs to the point of origin before proceeding to coat the next section of pipe. There is provided a shuttle arrangement whereby the coating plugs make a singie pass through the length of tube to be coated and pass into a retaining chamber at the opposite end of the pipe, and then return to the point of origin while coating a second length of pipe, thereby operating approximately twice as fast as the prior systems which use an arm or boom which, by the very nature thereof, require that the coating arm make a round trip before another length of pipe can be moved into position for coating.

Another object of this invention is to provide truncated conoid ends on coating applicators so that they may pass from retaining chambers into poorly aligned, irregular, and/ or elliptical tubings to be coated.

ln accordance with the present invention, there is provided a pipe coating system in which a pair of chambers are spaced apart the length of the pipe to be coated. Each chamber has one closed end and is coaxially disposed one with respect to the other with the open ends thereof facing each other. Coating applicators in one of the chambers confine a quantity of Huid coating material therebetween. Clamping means adjacent the open end of each chamber preferably are hydraulically actuated to grasp and align a pipe section coaxially with the chambers. ri`he clamping means is provided with a means to seal in huid-tight relation the juncture between the pipe and the open ends of the chambers. Means are then provided for developing pressure in one of the chambers to move the applicators and the coating material therebetween through the pipe in order to apply coating to the latter pipe. Provision is also made for developing pres- Patented Jan. 2l, 1954.

ICC

sure in the other chamber to return the applicators through a second pipe section to the first chamber so that the applicators shuttle back and forth between the two chambers through successive pipe sections aligned with the chambers for coating uniformly the interior of such pipe sections.

ln a more specific aspect of the invention there is provided a frame on which there is mounted a pair of open ended chambers coaxially aligned and having open ends facing each other at opposite ends of the frame. A collar-type seal hydraulically actuated is adapted to be moved lengthwise of the chamber to span the juncture between the chambers and a given section of pipe moved into alignment therewith so that there may be provided a substantially smooth-walled conduit extending between the open ends of the chambers. A pair of coating plugs are positioned in one of the chambers. Meansl are provided for introducing coating material into at least one of the chambers between the coating applying plugs whereupon the application of hydraulic pressure in one cylinder behind both plugs moves them, together with the coating material, through the aligned pipe section to spread the coating material on the interior wall of said aligned section. A vent in the second chamber toward which the coating plugs travel serves controllably to discharge any fluid ahead of the applicators from the second chamber. Upon delivery of a second section of pipe to a position between the chambers, the coating plugs hydraulically are moved in the first direction through the second section of pipe to return the applicators to the iirst chamber while coating the second section of pipe.

For further objects and advantages of the present invention and for a more complete understanding thereof, reference may now be had to the following description taken in conjunction with the accompanying drawing which illustrates a pneumatically actuated pipe coating system.

Referring now to the drawings, there is illustrated a system for coating the interior of a joint of pipe, such as the pipe Titi. The pipe 1t) is supported on a pair of rails 11 and 12 which in turn are supported by uprightsI 113 and i4 mounted on a frame base 15. Preferably the rails l1 and 12 form an inclined track along which the pipe l@ may roll until it is stopped by checks 16 and 17. Checks 16 and 17 are so located as to align the ends of pipe i0 with each of the open ends of a pair of chambers 20 and 21 to form a coaxial array. More particularly, the chamber 2i? is formed from a cylindrical pipe section which has an internal diameter preferably the same as the internal diameter of pipe 1li. The chamber 2d is mounted at the right hand end thereof by bolts 23, 24 which couple a closure flange Z5 to a plate Z6 on the frame standard 27. Frame standard 27 is secured at the base thereof to the frame base l5. Thus the cylinder Ztl is cantilever-supported and extends from the standard 27 so that the open end thereof may be brought into registration with the end of pipe 1i).

A pair of coating plugs Sti and 31 are positioned in chamber 20. The plugs 30 and 31 me of resilient material and are adapted to be moved along the length of the chamber 2li under hydraulic pressure applied to one or the other of the plugs with the ends of the plugs exed outwardly into engagement with the inner walls of the chamber 20. The plugs may be of the type generally disclosed in Patent No. 2,480,358 of Arvel C. Curtis et al., a coworker of applicant. However, it will be preferable that the plugs be formed of a resilient material through which there extends a mandrel such as mandrels 32 and 33. Mandrcl 32 forms a central core for the plug 30. The rubber material forming the plug body is molded around the left end of the mandrel 32. The right end of mandrel 32 extends slightly beyond the end of the plug 30 and is adapted to engage a plug stop 34. `In a preferred embodiment, the plugs have at least two portions of enlarged diameter such as to maintain circumferential contact with the walls of the chamber 20 at at least two points spaced along the length thereof. The plug 30 is provided with a plurality of channels such as channels 3S which extend between a face 36 of the plug 30 and the surface of the plug 30 at a point between the two contact zones 37 and 3S. The plug 31 is similarly con- Structed. The zone bet-Ween the face 36 of plug 30 and the face 40 of plug 31 receives a coating material in liquid form injected by way of conduit 41. A vent 42 is provided leading `from the chamber 20 at a point aligned with the conduit 41 so that as liquid coating ma terial is injected into the chamber 20 between the plugs 30 and 31 any air between plugs 30 and 31 may be vented to atmosphere.

When coating material is thus disposed between plugs 30 and 31, hydraulic pressure may then be applied to the right hand side of the plug 30 to move the plugs toward the open end of the chamber 20. In so doing,

liquid coating material travels back through the channels to the zone between the contact zones 37 and 38. The tapered surface of the trailing portion of the plug 30 as it approaches the contact zone 33 serves to wipe a cylindrical coating of material onto the inner wall of the chamber 20 and onto the inner wall of pipe 10 as the plugs are driven therethrough,

In order to facilitate the coating of the pipe section 10, a collar-type seal 50 is provided for grasping and for sealing in fluid-tight relation the juncture 51 between pipe and chamber 20. The collar-type seal is supported by a carriage 52 which is mounted on a track 53. The seal 50 preferably is in the form of a rubber tube closed upon itself and adapted to permit the injection thereinto of air under substantial pressure.

In the form illustrated, the seal includes a heavy rubber cylindrical membrane 50a which is clamped at opposite edges thereof to opposite ends of a short metallic cylinder 50b to effect a fluid-tight seal therebetween. The membrane 50a is clamped to the cylinder 50h by brackets 50c and 50d which receive a bolt 50e. Brackets 50c and 50d are circular in shape and have inner perimeters which partially encircle membrane 50a. to provide lateral support therefor so that development of pressure inside the membrane will cause a sealing force to be exerted on the outer surface of pipe 10 and chamber 20.

Seal 50 is initially deflated and the carriage 52 is moved along the track 53 to permit pipe section 10 to be rolled into position with the right end thereof adjacent to the end of the chamber 20. The carriage 52 is then moved so that the seal 50 is in registration with the juncture 51 between pipe 10 and chamber 20. Compressed air then expands seal `S0 into fluid-tight engagement with the eX- terior wall of the chamber and the pipe 10. When this is done, application of air pressure behind the plug moves the plugs 30 and 31 and the coating material therebetween through chamber 20 and into pipe 10. Travel of the plugs and the coating material through pipe 10 causes the deposit of a coating on the interior wall of the pipe 10.

At the left end of the pipe 410 there is provided a system which may be identical with that above described for the right encl of the pipe 10. The chamber 21 is sealed to the left end of pipe 10 by a second collar-type seal `60 which is supported from a carriage 61. Carriage 61 is movable along the chamber 20 on a track 62. The chamber 21 is cantilever supported from a frame standard 65 which in turn is mounted on the frame base 15. The closure disk 66 for chamber 21 includes a plug stop 67 which serves to arrest the travei of the plug 31 at the end of the chamber 20. A drain 68 is provided at the end of the chamber 2'1 and adjacent to the plug stop 67 for discharge of any fluid in pipe 10 or chamber 21 ahead of the plug 31.

ln a preferred form of the invention, the plugs 30 and 31 will be moved through the chambers 20 and 21 and pipe 10 under the force of compressed air selectively applied iirst to one chamber and then to the other. A supply line 00 leads from compressor 81 to a manifold 82. The manifold 82 is connected by way of valve 83 to the input line leading to the chamber 20. Manifold 82 is connected by way of valve S4 to the input line leading to the chamber 21. A flexible line 85 extends between a valve 86 leading from the manifold 82 and the seal 50. A flexible line 87 leads from a valve 8S connected to the manifold S2 to the seal 60. Valve 33 is coupled to a valve 90 in the drain line leading from chamber 20 and valve 84 is coupled to the valve 91 in the drain line leading from `chamber 21. The valves 83, 84, 86, S3, 90 and 91 are actuated under the control of a switch 100.

Valves 33, 84, 86, 88, 90 and 91 preferably are solenoid-actuated. Solenoid coils 101, 102 and 103 are provided for the control of the valves. Solenoid coil 101 is conected by linkage 101a to valves 83 and 90. Solenoid coil 102 is connected by way of linkage 102e and 102!) to valves 86 and `S8. Solenoid coil 103 is connected by way of linkage 10351 to the valves 84 and 91. A battery 105 is connected at one terminal thereof to the armature `10011 of a multiterm-inal switch unit 100. The other terminal of battery 105 is connected to the conductor common to each of the solenoid coils 101-103. When the armature 10011 is moved to the right, the solenoid coils 101 and 102 are energized to open valves 83, 86 and S3 and to close valve 90. This will serve simultaneously to clamp the seals 50 and 60 to the ends of the pipe :10 and to the ends of the chambers 20 and 21 and to apply cornpressed air behind the plug 30 to move plugs 30 and 31 through the pipe 10. When the armature 1000 is moved to the left, coils 102 and 103 are energized to open valves 84, 86 and 88 and to close valve 91. The seals 50 and 60 are thus simultaneously closed and compressed air is applied behind the plug 31 to move plugs 30 and 31 to the right from chamber 21 into a succeeding section of pipe.

In practice it will be desirable remotely to control movement of the carriages 52 and 61 relative to the charnbers 20 and 21, respectively, to permit removal of pipe 10, replacing the same with a succeeding section of the pipe to be coated. ln this case a hydraulic cylinder such as cylinder may be mounted adjacent the end of the track 53. A four-way valve 111 is connected to a supply line 82a and to a vent line 1106. Valve 111 serves selectively to apply hydraulic pressure to a piston 11025 in the actuator 110. This piston is connected by way of shaft 112 to the carriage 52 to provide an automatic carriage-positioning system. A supply line 32a is connected to a second four-way valve which serves to control a second hydraulic actuator 121 for movement of carriage 61 along track 62. Valves 111 and 1.20 are coupled together by a linkage 122 and preferably are solenoid-actuated under the control of a solenoid coil 123 by way of linkage 12.2. Coil 123 is connected by way of a control switch 1214 to the battery 105. Preferably the valves 111 and 112 are so connected so that upon closure of switch `124 compressed air from supply line 32a will be applied to the actuators 110 and 121 to move the carriages 52 and 61 into alignment with the juncture between chambers 20 and 21 and pipe 10. When switch 124 is opened, valves 111 and l120 are actuated to apply compressed air to the opposite ends of the actuators 110 and 1211 to retract the carriages S2 and 61.

Having described the structure of the system, it will now be understood that in ope-ration the plugs 30 and 31 initially will be positioned in one of chambers 20 or 21 (i.e., chamber 20) with coati-ng material injected therebetween. ySubstantial volume of coating material may thus be provided so that a plurality of pipe sections may be coated without having to reload the system with coating material. When the coating material is present between the plugs 30z and 31, a section of pipe such as pipe will be rolled against the stops 16 and 17. Switch 124 is then closed to position the carriages 52 and 61. ri`he switch armature 10021 is then actuated to open valves 83, 86 and 88 and to close valve 90. The pipe 10 is thus clamped into alignment with chambers and 21 and simultaneously movement of the plugs and 31 is initiated, t-ravel being towards the left. The plugs travel from the mouth of chamber 256 into the pipe 16 and through pipe lil into the chamber Ztl, coming to rest with the plug bumper or mandrel 3-3 of plug 31 engaging the end of the stop V617. At this time the switch 100 may be opened whereupon the air pressure in the line leading to the seals 5t)` and 6tlwill be relieved. Switch 124 is then opened to retract carriages 52 and 61. Stops 16 and 17, by means not shown, may release pipe 10 while a succeeding section of pipe is rolled into coating position adjacent stops 116 and v17. Switch 124i is then closed to position carriages 52 and 6-1 with the seals 5t) and ell in registration with the juncture between the ends of the new section of pipe and the ends of the chambers 2t? and 21. The switch armature ltlilzz is then actuated to open valves 84, Se and 8S and to close valve 91. Such action wil-l cause the seals Sti and 60' to clamp the junctures between the new section -o-f pipe and the ends of chambers 2t) and Z1. Simultaneously the plugs 3,9 and 31 will beigin their movement back through the chamber 2i1 into the new section of pipe and thence into the chamber 22 where their travel is arrested.

By this means the plugs form a shuttle-type coating system in which the volume of coating material restrained between the ends of the plugs Sti and 32 is repeatedly moved backwards and forwards through successive pipe joints in order to carry out a continuous coating operation with a minimum of handling.

Thus there is provided a pipe coating system in which the two chambers are spaced apart a distance according to the length of the pipe to be coated. Each chamber has a closed end and is coaxially disposed with Irespect to the other chamber with the open ends thereof facing each other. A pair of coating plugs positioned in one of the chambers contines a quantity of huid coating material therebetween. A pair of hydratdically-actuated clamps, one adjacent each open end of each chamber, is provided for grasping and aligning the pipe coaxially with the chambers, the clamping means having a means for sealing in huid-tight relation the junctures between the open ends of the chambers and the section of the pipe.. The hydraulic pressure applied to one of the chambers moves the applicators and the material through the pipe to apply coating to the pipe and to deliver the plugs and the unused supply of coating material to the chamber at the opposite end of the pipe whereupon a new section of pipe is placed into position and the plugs and the coating material are delivered through said new section back to the first chamber'.

It will be apparent that the thickness of coating applied to pipe section 10 will depend upon the velocity with which the plugs travel through the pipe and upon the pressure with which the contined coating material is forced onto the pipe walls. It has been found desirable to regulate the coating thickness by back pressure applied to the coating plug system. Such back pressure may bne developed in the present system as the plugs move from chamber Zit to chamber Z1 by applying pressure to chamber Z1 by way of valve 84. lnitia ly the same pressure is applied to both chambers 2i? and 21. Valves 90 and 91 may be of the form of constant pressure inlet valves where the valve inlet pressure is set to a level which is lower by a predetermined amount than that in chamber f2@ so that plugs 30l and 3d will be moved through pipe 10 under the diiferential pressure which is controlled by valve 91. With valve of the constant pressure inlet type, travel of plugs 30' and 3-1 from chamber 21 to chamber 2,0 would be controlled by pressure on the leading plug 30.

While the foregoing description has related to a system in which control is effected by means of compressed air, it will be appreciated that other systems may be employed. Air pressure, however, is preferable in that it does not react with the liquid coating as would a hydraulic system utilizing a solvent. Further, the compressed air may contain an additive which will effectively accelerate the curing and setting of the iilm on the inside of the pipe. Preferably the coating materials employed in :the present system are epoxy resins and vinyl compounds. Other suitable coating materials may be employed where they are capable of being spread by extrusion while in the liquid state and are such that they are then dry or set either with or without an accelerator after the application thereof. The coating plugs themselves preferably are double-opposed, truncated conoids with conoidal cavities in the outer ends through which the metal plug bumpers extends and support the molded rubber plug body. A suitable metering system may be connected to the coating supply line 41 in order to provide control information for the coating operation.

While not shown, the frame standards 27 and 65 may be made adjustable along frame 15 to accommodate different pipe lengths. Pipes of dilferent diameter may also be treated by substituting chambers and clamps of suitable diameter where needed.

Having described the invention in connection with a certain speciiic embodiment thereof, it is understood that further modications may now suggest themselves to those skilled in the art and it is intended -to cover such modifications as fall within the scope of the appended claims.

What is claimed is:

l. A system for coating pipe interior which comprises a frame, a pair `of coaxially yaligned cylindrical chambers mounted on said frame each open at one end and spaced apart a predetermined distance, means on said frame for supporting a length of pipe with the ends thereof adjacent to and facing the open ends of said chambers, means on said frame at each end of said pipe movable along said frame and including power actuated elements operable temporarily to seal said chambers to the ends of said pipe, means for introducing a coating material into at least one of said chambers, exhaust means adjacent the closed end of the other of said chambers, a pair of coating applying plugs in said one of said chambers for confining said coating material therebetween, and means operable in predetermined timed relation to actuation of said power actuated elements for introducing a pressurized iiuid into said one of said chambers to move said plugs and said coating material from said one of said chambers to said other of said chambers to coat the interior of pipe clamped therebetween.

2. A `system for coating the inside of pipe which comprises a pair of cylindrical chambers each open at one end and of inside diameter corresponding with the inside diameter of said pipe, -frame means for supporting said chambers coaxially with the open ends facing each other spaced apart a predetermined distance to receive ya length of said pipe therebetween, uid `actuated clamping means adjacent the facing ends of each of said chambers for sealing in fluid-tight relation the ends of said pipe to the ends of said chambers, 'a pair of applicators in one of said chambers, a flow channel for introducing a coating material between said applicators, a source of pressurized fluid, a pressure control system interconnecting said source and said chambers having a irst valve-controlled entry port leading into said one of said chambers at a References Cited in the e of this patent point adjacent to the closed end and a first valve-conn .w rolled exhaust port leading from said one of said cham- UNITED QTATES l ATENN chambers selectively actuated upon actuation of said clamping means to open said second entry port and close said second exhaust port to apply pressure to said pair of applicators to return them to said one of said chambers.

311,319 Great Britain July 7, 1930 

2. A SYSTEM FOR COATING THE INSIDE OF PIPE WHICH COMPRISES A PAIR OF CYLINDRICAL CHAMBERS EACH OPEN AT ONE END AND OF INSIDE DIAMETER CORRESPONDING WITH THE INSIDE DIAMETER OF SAID PIPE, FRAME MEANS FOR SUPPORTING SAID CHAMBERS COAXIALLY WITH THE OPEN ENDS FACING EACH OTHER SPACED APART A PREDETERMINED DISTANCE TO RECEIVE A LENGTH OF SAID PIPE THEREBETWEEN, FLUID ACTUATED CLAMPING MEANS ADJACENT THE FACING ENDS OF EACH OF SAID CHAMBERS FOR SEALING IN FLUID-TIGHT RELATION THE ENDS OF SAID PIPE TO THE ENDS OF SAID CHAMBERS, A PAIR OF APPLICATORS IN ONE OF SAID CHAMBERS, A FLOW CHANNEL FOR INTRODUCING A COATING MATERIAL BETWEEN SAID APPLICATORS, A SOURCE OF PRESSURIZED FLUID, A PRESSURE CONTROL SYSTEM INTERCONNECTING SAID SOURCE AND SAID CHAMBERS HAVING A FIRST VALVE-CONTROLLED ENTRY PORT LEADING INTO SAID ONE OF SAID CHAMBERS AT A POINT ADJACENT TO THE CLOSED END AND A FIRST VALVE-CONTROLLED EXHAUST PORT LEADING FROM SAID ONE OF SAID CHAMBERS THEREOF SELECTIVELY ACTUATED UPON ACTUATION OF SAID CLAMPING MEANS TO OPEN SAID FIRST ENTRY PORT AND CLOSE SAID FIRST EXHAUST PORT TO MOVE SAID APPLICATORS THROUGH SAID LENGTH OF PIPE, A SECOND VALVE-CONTROLLED ENTRY PORT LEADING INTO THE SECOND OF SAID CHAMBERS AT A POINT ADADJACENT TO THE CLOSED END THEREOF AND A SECOND VALVECONTROLLED EXHAUST PORT LEADING FROM SAID SECOND OF SAID CHAMBERS SELECTIVELY ACTUATED UPON ACTUATION OF SAID CLAMPING MEANS TO OPEN SAID SECOND ENTRY PORT AND CLOSE SAID SECOND EXHAUST PORT TO APPLY PRESSURE TO SAID PAIR OF APPLICATORS TO RETURN THEM TO SAID ONE OF SAID CHAMBERS. 